Furnace and furnace draft control



1932- F. x. LAUTERBUR ET AL FURNACE AND FURNACE DRAFT CONTROL Filed 001:. 30, 1929 4 Sheets-Sheet l 1932- N F. x. LAUTERBUR ET AL 4 1, 00

FURNACE AND FURNACE DRAFT CONTROL Filed Oct. 30, 1929 v 4 Sheets-Sheet 2 i 1 5 l I r i I v INVENTOR.

ATTORNEYS 1 1932- F. x. LAUTERBUR ET AL 1,891,100

FURNACE AND FURNACE DRAFT CONTROL I Filed Oct. 50, 1929 I 4 Sheets-Sheet 5 Dec. 13, 1932. F. X. LAUTERBUR ET AL 1,891,100

I N VEN TOR.

A TTORNE Y5 in, an

Application lled number no, 19529. Serial No. 503,5011,

r. on sinner, omio @ur invention relates to furnaces, and particularly to solid fuel burning furnaces for domestic heating plants, and to draft control systems for such furnaces.

It is the object of our invention to provide a heating furnace in which a blast of air causing a forced draft is automatically controlled in accordance with more than one variable condition. It is another object of our in- 1 vention to provide movable bafiles which will avoid irregular consumption of the fuel due to variation in an induced draft and a natural draft. A still further object is to provide means for conveniently moving the to: ba'fies or'draft preventing devices so that the ashes from the burning fuel may be readily removed from the furnace.

ln the controls for the forced draft of air blasts it is an object of our invention to provide a blast producing device which will 7 be automatically controlled .by a thermostat or by a thermostatic switch so positioned relative to the fuel support lines as to be effective to prevent the forced draft from beas ing too active on the fuel line and get down dangerously close to the grate bars.

A still further object is to provide a control system which will be manually controlled either independently or in combination with a damper control, so that the amount of draft induced may be regulated in accordance with seasonal requirements.

The above and other objects, such as improvements in elliciency and cheapness of cost of construction, we accomplish by that certain combination and arrangement of parts of which we have shown several preferred modifications. g lfn the drawings A on Figure l is a diagrammatic, vertical, seciiorlial view showing one type of draft conro Fi 'ure 2 is a sectional plan view, the section eing on the line 2-2 of Figure l. as Figure 3 shows in die rammatic, vertical section another type of raft control.

Figure 4 is a diagrammatic plan view of the blast pipe shown in Figure 3, such as would appear if taken along the lines H in to Figure 3..

Figure 5 is a sectional plan view, the sec ticn being on the line 55 of Figure 3.

Figure 6 shows another preferred draft control arrangement in diagrammatic ver tical section.

Figure 7 is a sectional plan view, the section being on the line 7?' of lFi re 6.

Figure 8 shows another modi -ed type of draft control arrangement in diagrammatic vertical section.

Figure 9 is a sectional plan view, the section being on the line 9-9 of Figure 8.

Referring first to the diagram in Figure l, we have shown the fire pot 1 encased in the usual furnace casing 2. Grate bars 3 are 65 shown which support the fuel bed. The forced draft is caused by a fan 4- preferably coupled with an electric motor 5. The forced draft from the fan enters the furnace through a pipe 6. T he pipe 6 is coupled with a tubum lar ring 7 having discharge orifices 8 through which the draft is directed downwardly at the sides of the fuel bed as indicated by the direction of the arrows.

The control for the blower is provided from 75 electric current supply lines 9. These lines are coupled in series with a thermostat l0, and with thermostatic switches 11 which control directly the operation of the motor. We have indicated the flue outlet 12 having a so check damper 13 therein which may be manually controlled from a house control regulator I l by means of a chain 15.

For controlling the speed of the electric motor which actuates the blower fan, we have 85 provided a rheostat 16. As a semi-automatic control for the rheostat, we have connected the check damper 13 by means of a chain 1? with the rheostat.

The operation of this system is as folac lows :When the temperature falls below a certain level, the thermostat 10 causes the motor to be energized. llhis is providing that the fuel line is not suficiently close to the grate bars to afi'ect the thermostatic .95 switches 11. In case the fire has burned down too low, the thermostatic switches 11 will prevent the starting of the motor. Should the manual control It in the house be set for the check damper to be slightly open, the rheo- 10 stat will be correspondingly affected, and the motor will not operate at its. normal high speed. Thus, in the spring and fall, when it is not necessary to force the furnace, and less strong blasts will be introduced into the furnace, a great economy in the consumption of fuel will be made possible.

Referring now to Figure 3, we have shown the fire pot 1a. encased within the furnace casing 2a with a forced draft caused by a fan 4a actuated by a motor 5a. A spider 7a is placed within the furnace under the grate bars 3a, and as the-discharge orifices 8a are directed upwardly the air blast will be introduced through the fuel bed in the direction of the arrows. The conduit connecting the blower and the spider is indicated at 6a.

The automatic control for the motor in this instance is the combination of a thermostat 10a supplied with current from feed lines 9a with a thermostatic switch 11a in series with the feed lines so that even should the thermostat move to its low position so as to turn on the electric motor, if the fire within the furnace was dangerously low the thermostatic switches would prevent the motor from starting.

In the control arrangement shown in Figure 3, we have also provided a rheostat 16a so that the electric motor 5a may be set for variable speeds of operation.

In Figures 6 and 7 we have shown the fire pot 17) mounted within the furnace casing 212. Grate bars 3?) support the fuel bed and a blower fan 41) actuated by a motor 5?) induces a forced draft through the conduit 6?) into the spider 7 b. The blast orifices 8b in the spider 7 b are directed downwardly and outwardly to cause the air blast to penetrate the fuel in the directions indicated by the arrows.

In Figures 6 and 7 we have shown a similar control system as thatshown in Figures 3-5. We have shown the thermostat 10b supplied with current from the power feed lines 9?), and with thermostatic switches 11?) in series with the feed lines to the electric motor. We have also shown a manually operable rheostat 166.

In Figures 8 and 9'we have shown a furnace having the usual fire pot 10 mounted within the casing 20, and with grate bars 30 to which a forced draft is supplied from a pipe having discharge orifices 80 which direct an air blast up through the grate bars in the direction indicated by the arrows. The pipe 70 is spaced a short distance below the grate bars and the blast of air passes to the pipe 70 through the pipe 60 from the blower 4c which is actuated by the electric motor 50.

The control for the motor which operates the blower is similar to; that shown in Figures 3 and 6. A thermostat 100 is supplied with current from power feed lines 90 and thermostatic switches 110 which are affected by the temperature at the fuel line within the furnace, control the starting and the stopping of the motor at such speed as is manually set on the rheostat 160. It will be understood that thermostats 10, 10a, 10?) are thermostatic switches.

It will thus be apparent that we have provided draft control systems which will enable very accurate control, either entirely automatic or semi-automatic, so that the rate of fuel consumption may be very efficiently regulated.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent, is i 1. In combination with a furnace, means to induce a forced draft in the furnace, means for starting the operation of said draft-inducing means upon a predetermined low temperature in a space to be heated by the furnace, and means preventing starting.

of said operation if there is a predetermined low temperature in the furnace.

'2. In combination with a furnace, a blow- I er, a motor, driving said blower, an inlet from the blower to the furnace, and thermostatic switches in series with said motor and with each other, one switch exposed to influence of temperature in a space to be heated by the furnace, closing the circuit upon a predetermined low temperature in said space, and the other switch exposed to influence of temperature in the furnace and opening the circuit upon predetermined low temperature in the furnace.

3. In combination with a furnace and its outlet for combustion products, a damper affecting flow of the products through said outlet, means to induce a forced draft in the furnace, means for starting the operation of said draft-inducing means upon a predetermined low temperature in a space to be heated by the furnace, means preventing startin of said operation if there is a predetermined low temperaturein the furnace, and means for decreasing the rate of operation ofsaid draft inducing means as said dam er is operated to retard the flow of combustion products through said outlet.

4. In combination with a furnace and its:

opening the circuit upon predetermined low temperature in the furnace, and a rheostat in,

series with said switches and the motor and connected to said damper to increase the remomoo sistance in said circuit and slow the operation of the motor upon operation of the damper to retard the flow of combustion products through said outlet.

FRANK X. LAUTERBUR, EDWARD J. LAUTERBUR. 

